@ROTFL I can not test it.
Please report the issue to Vivaldi. May be this issue is a bug.
Please read how to Report a bug for Vivaldi carefully and then report the bug to Vivaldi bugtracker.
//Edit: If you make a screen recording (GIF, Video) and send them, it would be easier to test and understand the issue.

@cdobrich under vivaldi settings>search
I have everything unchecked except "show search field in address bar". So maybe uncheck something there. Probably "search in address field"
I only get bookmarks when typing there now because under settings>address bar>address field dropdown, only bookmarks is checked.

+1
Guys, I do also want to see a better implementation for the domain expansion, for that reason I proposed a generalized solution which supposed to solve this issue and other more.
Do you believe it is a satisfying solution (please refer to example no. 2) and do you think it properly encompass the issue discussed here ?

I'm not a fan of the tab solution...
For me, the best behavior would be using the down key instead of the tab key. I know that even multiple tabs have a meaning of cycling through the option on a command line, but in a browser I use tabs to cycle through controls on a page, not for other things...
If I type forum.vival and then Enter, the browser would try to go to http://forum.vival ;
If I type forum.vival, then the Down key and then Enter, it might go to this page, for instance, if it was the first in the dropdown
And if I want the second or third in the dropdown, I just press down a few more times. As a matter of fact, that's already how it works So the only thing to implement, really, is to stop autocompleting so aggressively (and granted, the default could still be as is, as that seems to be an industry standard, and the option not to autocomplete would be just fine for me).

@fightmilk said in Add Chrome-Like URL Completion & Quicksearch:
let's not let ego or our pride in being better than Chrome users hurt ourselves.
This is not a motive of Vivaldi developers. Functions are not eliminated or blocked to spite Chrome.

Not what is requested here, but a tip to work around the problem.
Go to https://www.bbc.co.uk/news/world/us_and_canada
Then Ctrl+Click on the URL to go up to a parent folder:
Ctrl+Click to go to the Root Folder